Horsetail (Equisetum sp.): Identification, Uses, and Benefits

Horsetail (Equisetum sp.) is a living-fossil plant that’s been around since the time of the dinosaurs, and it shows up just about anywhere with damp soil. Learn how to identify horsetail, tell it apart from its look-alikes, and make use of its edible spring shoots and silica-rich green stems for tea, tincture, and salve.

Horsetail is one of those plants you’ve probably walked past hundreds of times without recognizing. It grows in marshes, ditches, woodland edges, gardens, and disturbed soil all over North America, and it has the distinction of being a true living fossil. The genus Equisetum is the only surviving member of an ancient order of plants that dominated Earth’s forests for about 100 million years during the Paleozoic, and the oldest known relative of modern horsetail dates back roughly 375 million years. The plants you see today are direct descendants of that prehistoric lineage, scaled down to a couple of feet tall.

Foragers and herbalists know horsetail for a few different uses. The early-spring fertile shoots come up first, and they’re a tender wild vegetable with a sweet bean-sprout crunch when prepared carefully. The sterile green shoots that follow are silica-rich, tough as a nail file, and the part herbalists harvest for tinctures, teas, and salves. Both stages have their place, and both show up in early spring alongside other classic spring wild edibles like ramps, wild asparagus, and fiddlehead ferns.

What Is Horsetail?

Horsetail or Equisetum species are a genus of about 20 herbaceous perennial ferns that reproduce through spores rather than seeds. The plants of this genus are sometimes called living fossils because they are the only living genus in the order Equisetales. For about 100 million years, this once-diverse order of plants dominated the earth’s Paleozoic forests. Horsetail’s oldest known relative, Pseudobornia ursina, dates to approximately 375 million years ago.

Today, horsetail species are known by many common names, including Snakegrass, Skeletonweed, Bottlebrush, Scouringrush, Foxtail, Mare’s Tail, Scourweed, Pinetop, Horse Pipes, or Puzzlegrass. There are horsetail species native to parts of North America, South America, Asia, Europe, and Africa.

In North America, there are many species of horsetail that you may come across. These include Common or Field Horsetail (Equisetum arvense), Water or Swamp Horsetail (Equisetum fluviatile), Marsh Horsetail (Equisetum palustre), Meadow Horsetail (Equisetum pratense), Wood Horsetail (Equisetum sylvaticum), Great Horsetail (Equisetum telmateia), Rough Horsetail (Equisetum hyemale), Smooth Horsetail (Equisetum laevigatum), Dwarf Horsetail (Equisetum scirpoides), and Variegated Horsetail (Equisetum variegatum).

Is Horsetail Edible?

Some horsetail species are edible and others are not, so the first step is making sure you’ve identified the right species. Common Horsetail (Equisetum arvense) is the species most foragers and herbalists mean when they talk about edible horsetail, and it’s the species most of the medicinal research has been done on. Great Horsetail (Equisetum telmateia) is also generally considered edible, and some foragers find it especially tasty. Most other species are best left alone for the kitchen, even if they’re useful for scouring or other non-food applications.

The species to specifically avoid is Marsh Horsetail (Equisetum palustre), which contains palustrine and palustridiene alkaloids in addition to the thiaminase shared by the rest of the genus. Marsh horsetail is documented as one of the most poisonous plants of wet grasslands in the northern hemisphere, and it’s a real concern in the boggy or swampy habitats where it tends to grow. Since marsh horsetail and the edible species can occur in overlapping ranges, it’s worth knowing this one cold before you harvest from any wet area.

Even with a confirmed edible species, all horsetails contain thiaminase, an enzyme that breaks down vitamin B1 (thiamine). Thiaminase is destroyed by heat or thorough drying, so cooking the shoots, drying the green stems for tea, or extracting them in alcohol for tincture all neutralize this concern. Long-term raw consumption is the situation to avoid. Most modern herbal references also recommend capping internal use of horsetail at around 6 weeks consecutive, with a break before resuming, to avoid cumulative thiamine depletion.

Beyond thiaminase, horsetail contains small amounts of nicotine, so don’t take horsetail if you have a nicotine allergy or are currently using nicotine patches, pills, or gum. It may also lower the levels of thiamine and potassium in the blood, so you should avoid taking horsetail if you have a chronic drinking issue, heart arrhythmia, or are currently taking digoxin. Horsetail may also interfere with the body’s ability to eliminate lithium, so those taking lithium should avoid it.

Horsetail may also affect the liver. While there is little evidence that oral consumption of horsetail causes liver injury, experts recommend that people with existing liver disease or cirrhosis don’t take high doses of horsetail for an extended period. Horsetail is sometimes used as a mild diuretic, so if you’re already taking diuretics, you should avoid it as it could lead to dehydration.

Horsetail and Livestock

Horsetail is toxic to horses and cattle, and the risk is more serious than the “mildly toxic” framing many older sources use. Horses don’t typically choose to eat fresh horsetail, but it’s a real problem when it ends up in hay, where they can’t sort it out. Horses consuming about 20 to 25% horsetail in their diet will exhibit neurological symptoms within about three weeks, and lower levels can cause colic and other gut issues. If you have horses, it’s worth scouting any pastures or hay sources for horsetail before there’s a problem. Cattle face similar risks, and Marsh Horsetail in particular is a documented hazard in wet pastures across the northern hemisphere.

Horsetail Medicinal Benefits

As a living fossil, it’s no surprise that humans discovered how to use horsetail long ago. In ancient Rome and Greece, herbalists used horsetail to treat kidney problems, tuberculosis, ulcers, bleeding, and wounds. Europeans continued using the plant to treat bladder and kidney conditions. Native Americans also taught European colonists to use horsetail as a diuretic tea and a cough medicine for horses.

Modern scientists have been exploring horsetail’s healing effects. One promising use of horsetail has been in supporting bone health and aiding in bone healing.

One study found that horsetail inhibits osteoclasts, which break down bone and can become overactive in people with osteoporosis. On the flip side, another study found that horsetail also stimulates osteoblasts, which are responsible for bone synthesis and remodeling. Further, a study found that horsetail supplementation improved bone density in rats.

Researchers believe some of these healing effects may be from horsetail’s mineral content. Up to 25% of the plant’s dry weight is silica. Silica is present in bones and cartilage and helps with formation and density.

Modern research has also verified the historical use of horsetail as a diuretic. One small study found that horsetail was a more effective diuretic in healthy individuals than a common diuretic medication. Another study on mice also found that horsetail was as effective as a pharmaceutical diuretic.

The ancients were also on to something when they used horsetail for wound healing. One modern study found that a horsetail ointment encouraged wound healing and reduced pain, swelling, and redness in patients with wounds from an Episiotomy or surgical cut for childbirth.

Some of horsetail’s wound healing effects may come from its antimicrobial activity. One study found that horsetail extract was effective against gram-positive cocci bacteria. Another study found that horsetail had strong antimicrobial effects on various bacteria strains and fungi, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis; fungi: Aspergillus niger and Candida albicans.

Where to Find Horsetail

Horsetail has an extensive range worldwide, and there are species native to parts of North and South America, Africa, Europe, and Asia. Here in the United States, there are several native species. One species, Common Horsetail (Equisetum arvense), is found in all U.S. and Canadian states.

Generally, the horsetail species you’ll find in the United States prefer areas with damp, slightly alkaline, or neutral soil, though occasionally, some species occur in acidic soil. You’ll often find horsetail growing where you’d find other fern species where the ground is soft and moist. Some species, like Common Horsetail (Equisetum arvense), will tolerate dry areas easily as long as they have some moisture to get established.

Horsetail may grow in stream edges, swamps, marshes, woodlands, pastures, gardens, disturbed areas, and roadsides. Some species, like the Meadow Horsetail (Equisetum pratense), are early succession species that only occur in recently opened or disturbed areas such as those created by water erosion.

When to Find Horsetail

Horsetail usually comes up in early spring. As it likes moist soil, it generally thrives during spring rains. The fertile stems come up first and release their spores in April or May. As these wither, the sterile, green stems come up. These horsetail stems may be present throughout the summer until frost, depending on the conditions.

You will have a relatively short period in April or May to harvest the fertile brown shoots for culinary use. You can also use the sterile green shoots that come up later. Usually, herbalists use these green shoots for medicinal preparations. However, you can still use them in culinary preparations if you catch them early before the leaves have folded down.

Generally, it’s best to harvest horsetail’s sterile shoots in spring and early summer for medicinal use. Later in the summer, horsetail’s mineral and silica content increases, making it harder for the body to process. Look for bright green leaves pointed upward and outward. Drooping, discolored leaves are generally found on older plants.

Identifying Horsetail

Horsetail begins the year by sending up a short-lived, whitish or brown, fertile stem with a spore-producing cone on the top. After these fertile shoots, horsetail produces sterile, green shoots that resemble miniature pine trees.

You’ll often find colonies of the plants growing together as they spread by spores and underground by rhizomes.

While most horsetail species share some general characteristics, you may find significant variation with different species or over the plant’s extensive range.

Horsetail Leaves

Horsetail leaves are arranged in whorls just above the nodes of the sterile green stems. They are slender, hollow, green, or green-black and may be branched or unbranched, depending on the species. From a distance, these leaves look much more like needles than leaves. Some species may have 40 leaves in a single whorl.

On some species, like the Dwarf Horsetail (Equisetum scirpoides), the leaves are tiny and barely noticeable. They may only reach 1 millimeter in length. People often list Rough Horsetail (Equisetum hyemale) as leafless as the leaves are minuscule and form tiny black-green bands at each of the stem joints. On large species like the Great Horsetail (Equisetum telmateia), leaves may be up to 8 inches long.

Horsetail Stems

Horsetail has two distinct types of stems or shoots. Both types are round and usually have ridges, though the number varies with species. For example, Great Horsetail (Equisetum telmateia) stems typically have 20 to 40 ridges around them, while Common Horsetail (Equisetum arvense) usually only has 10 to 15 ridges.

The first stems that appear in spring are fertile, spore-producing stems. These stems are usually whitish to brown. They have a cone-like structure at the top of the stem that produces spores. Most species, like Common Horsetail (Equisetum arvense), feature brown, papery sheath around each node.

As the first stems wither, horsetail sends up hollow, jointed, green stems with whorled leaves. Many species have a miniature pine tree-like appearance.

Horsetail’s stem height varies significantly with species. One of the tallest horsetail species is the Great Horsetail (Equisetum telmateia), which regularly reaches 15 feet or more. One of the shortest species is the Dwarf Horsetail (Equisetum scirpoides), which may reach 11 inches tall. One of the most widespread species, Common Horsetail (Equisetum arvense), usually grows about 1 to 2 feet tall.

Horsetail Flowers and Spores

Horsetail is one of our unique non-flowering plants that reproduces like ferns. Rather than produce flowers and seeds, it produces brown, cone-like structures on top of brown stems that release spores in April and May.

Horsetail Roots

Horsetail often spreads through underground rhizomes, which can grow more than 12 feet long and extend 6 feet or deeper, depending on the species. You will often find the plants growing in large clusters with many stems growing from the same rhizome.

Horsetail Look-Alikes

A few other plants look enough like horsetail to confuse newer foragers, especially in early spring before the plants have filled out. Most are easy to distinguish once you know what you’re looking at.

Japanese Knotweed

Horsetail may be mistaken for Japanese Knotweed (Reynoutria japonica) when small. However, it differs in a couple of ways:

• Japanese Knotweed shoots are plump and often leaning or crooked.
• Japanese Knotweed stems lack ridges.
• Japanese Knotweed shoots are reddish with purple dots.
• Japanese Knotweed shoots quickly begin to develop spade or heart-shaped leaves.
• Japanese Knotweed grows into a large 10 to 13-foot tall plant.

Common Rush

Horsetail can also be confused with the Common Rush (Juncus effusus). Thankfully, there are a few easy ways to tell them apart:

• Common Rush stems are smooth and lack ridges, nodes, or joints.
• Common Rush stems are filled with a light pith.
• Common Rush leaves form a brown sheath on the lower stem.
• Common Rush produces a yellowish flower cluster that emerges from one side of the stem near the top.

Native Bamboo or Cane

Lastly, horsetail is sometimes thought to resemble our native bamboo or cane species (Arundinaria spp.). You can differentiate them in the following ways:

• Native bamboo shoots lack the cone-like structure of fertile horsetail shoots.
• Native bamboo has tough, flexible, woody stems.
• Native Bamboo stems lack ridges.
• Native bamboo has fan-like clusters of leaves called top knots.
• Native bamboo has linear, lanceolate, or ovate-lanceolate leaves.

Ways to Use Horsetail

In spring, the brown, fertile horsetail shoots may not look like much, but they are a tasty wild vegetable. Harvest the shoots with a clean knife or pair of scissors, the way you would harvest wild asparagus. Remove any brown papery sheaths on the shoot.

The fertile shoots are mild, tender, and juicy, with a crunchy texture and a slightly sweet aftertaste. In the kitchen, they’re great for adding to stir-fries, quiches, and stews with other flavorful vegetables like garlic and onions. Cooking the shoots also takes care of the thiaminase concern noted above, so quick-cooking preparations like a stir-fry or sauté are an easy way to enjoy them safely.

You may want to experiment with different horsetail species in your area. Some foragers find certain species, like the Great Horsetail (Equisetum telmateia), especially tasty. Some species, especially Rough Horsetail (Equisetum hyemale), have very high silica levels, making them generally tough and unpalatable.

Usually, herbalists use the sterile, green stem that comes up a little later. You can use the green stems to make teas, tinctures, and salves. Herbalists and researchers have found that this silica-rich plant may help with wound healing, pain, bone density, and some specific urinary issues.

To preserve these sterile shoots for later use, you can tincture or dry them. To dry your horsetail, chop or cut it up into smaller sections with scissors. Drying can take a long time, and you may need to use a dehydrator because horsetail contains a lot of water. When fully dry, you can store it in an airtight container out of direct sunlight and use it for teas and other medicinal or cosmetic preparations.

Horsetail has many other uses outside the realms of cooking and herbalism. Native Americans used horsetail as a dye and to scour and polish wood and other materials. Two of the plant’s other common names, Scouringrush and Scourweed, probably stem from the Europeans’ use of the plant to scour pots, pans, and other objects made of pewter or tin. Folk tradition suggests that medieval knights also used the plant to shine their armor. These practices were probably most used with silica-rich Rough Horsetail (Equisetum hyemale), often known by the moniker Scouringrush.

Horsetail Recipes

• Reap the benefits of horsetail’s high silica content with this simple Horsetail tea recipe from Recipes from the Wild.
• Check out this video from Taiji’s Kitchen to learn to make two Japanese side dishes, Tsukudani and Tamago Toji, with horsetail.
• Use horsetail and other herbs to help soothe troublesome pain with this recipe for an Aches and Pains, Strains and Sprains Tincture/Liniment from The Herbal Academy.
• You can also use horsetail to clean your teeth. Test out this Horsetail Toothpaste recipe from Danu’s Irish Herb Garden.
• Get crafty and make your own natural Horsetail ink with this lovely video from Alex Boone Art!
• Elise Krohn from Wild Foods and Medicines has excellent instructions for a horsetail hair rinse that will help keep your hair silky and shiny.

Horsetail FAQs

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